Colors and sRGB

Heyo, :v:

i am struggling with a little problem right now…

i think i somehow have to disable sRGB, but i dont really know how!

The Problem:

image

This Color has the value (123,0,255) (All fine!)

But now i click on play with my Post Process Material (PPM) enabled and i take a screenshot of my Character who uses the PPM!

image

Now the color value suddenly is (114,0,255) so 9 “points” off…

I really need the exact color values for a movement tracking system/programm.

What can i do to stop these deviant colors… i am clueless…

Thank you guys in advance :blush:

I have a similar, if not the exact same, problem.

Even if I just pick a simple emissive color, I don’t understand why it gets blown out.

For example:

Being simply emissive, why is the preview brighter than the color I selected? It’s unlit, opaque, emissive only.

This is killing me for our broadcast AR/VS. For example, this test pattern:

There’s no question it should just render as shown when no other processing is happening to it - and this is not even in the level, with any post-processing features enabled, this is just in the material editor itself.

I’ve seen where people suggested the gamma was off, and to raise to the power of 2.2. That made it far too dark, but with playing around I could match the level of brightness (1.45 was the “magic” number), more or less, with the gray areas - but the colors are just off. If I disable sRGB, and set the texture parameter to linear color, it just gets worse.

To make matters worse, if I had to tweak texture images to make them work, it would be one thing - but being live broadcast use, we are getting live video and images from outside sources, and they come in blown out. Even if turning off sRGB helped, I don’t see a way to do it with a Texture2D downloaded from our image server on the fly.

Hey!

What you’re seeing here is the result of the standard UE tonemapping taking place. This also happens in the preview window of the material editor. If you switch either window’s view mode from ‘Lit’ to ‘Unlit’ you will see your colours reproduced exactly as you expect them.

Here are a couple of relevant forums posts:

At the end of that second one you can see a really simply post processing material setup for replacing the tonemapper, so that it will look like the unlit mode.

Heyo thanks for the tutorials.

The first one didnt help for my problem but maybe for @fhaab!
The second one only changes the way the whole scene looks. So at first i thought that would be great and it would change something. But in the End after applying my Post Process Material everything gets overridden… and i still have the same problem.

I already tried some other Tutorials like this one:

https://dev.epicgames.com/community/learning/tutorials/LEKn/unreal-engine-using-custom-stencil-to-selectively-bypass-postprocessing

So i thought maybe all the other settings in the Post Process Material may be influencing this… But the Pixel Values are different in 3 instances!

  1. In the Material Editor (they are like i want them there!)
  2. In the Viewport (They are already different)
  3. In the Render (They are different from the Viewport AND the Material editor…)

I have to do this for work and i really have no Idea about Materials… normally someone else is doing this :sweat_smile:

With how many are now using Unreal for film and broadcast, I’m finding it hard to believe there is still no good solution to this.

EPIC doesn’t have to change the default behavior, just a toggle to turn it off. Apparently all the hacks, like replacing the tone mapper, still don’t fully give an image that looks like the source.

The normal recommendation from the color scientists here when people are looking for “I have an input value that I want to be the output value” is to set the Tone Curve Amount to 0, Expand Gamut to 0, and Blue Correction to 0.